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/* Copyright (C) 1989-2020 Free Software Foundation, Inc.
Written by James Clark (jjc@jclark.com)
This file is part of groff.
groff is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation, either version 3 of the License, or
(at your option) any later version.
groff is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include <assert.h>
// 'class ITABLE(T)' is the type of a hash table mapping an integer (int >= 0)
// to an object of type T.
//
// 'struct IASSOC(T)' is the type of a association (pair) between an integer
// (int >= 0) and an object of type T.
//
// 'class ITABLE_ITERATOR(T)' is the type of an iterator iterating through a
// 'class ITABLE(T)'.
//
// Nowadays one would use templates for this; this code predates the addition
// of templates to C++.
#define ITABLE(T) T ## _itable
#define IASSOC(T) T ## _iassoc
#define ITABLE_ITERATOR(T) T ## _itable_iterator
// ptable.h declares this too
#ifndef NEXT_PTABLE_SIZE_DEFINED
# define NEXT_PTABLE_SIZE_DEFINED
extern unsigned next_ptable_size(unsigned); // Return the first suitable
// hash table size greater than the given
// value.
#endif
// Declare the types 'class ITABLE(T)', 'struct IASSOC(T)', and 'class
// ITABLE_ITERATOR(T)' for the type 'T'.
#define declare_itable(T) \
\
struct IASSOC(T) { \
int key; \
T *val; \
IASSOC(T)(); \
}; \
\
class ITABLE(T); \
\
class ITABLE_ITERATOR(T) { \
ITABLE(T) *p; \
unsigned i; \
public: \
ITABLE_ITERATOR(T)(ITABLE(T) *); /* Initialize an iterator running \
through the given table. */ \
int next(int *, T **); /* Fetch the next pair, store the key \
and value in arg1 and arg2, \
respectively, and return 1. If \
there is no more pair in the \
table, return 0. */ \
}; \
\
class ITABLE(T) { \
IASSOC(T) *v; \
unsigned size; \
unsigned used; \
enum { \
FULL_NUM = 2, \
FULL_DEN = 3, \
INITIAL_SIZE = 17 \
}; \
public: \
ITABLE(T)(); /* Create an empty table. */ \
~ITABLE(T)(); /* Delete a table, including its \
values. */ \
void define(int, T *); /* Define the value (arg2) for a key \
(arg1). */ \
T *lookup(int); /* Return a pointer to the value of \
the given key, if found in the \
table, or NULL otherwise. */ \
friend class ITABLE_ITERATOR(T); \
};
// Values must be allocated by the caller (always using new[], not new)
// and are freed by ITABLE.
// Define the implementations of the members of the types 'class ITABLE(T)',
// 'struct IASSOC(T)', 'class ITABLE_ITERATOR(T)' for the type 'T'.
#define implement_itable(T) \
\
IASSOC(T)::IASSOC(T)() \
: key(-1), val(0) \
{ \
} \
\
ITABLE(T)::ITABLE(T)() \
{ \
v = new IASSOC(T)[size = INITIAL_SIZE]; \
used = 0; \
} \
\
ITABLE(T)::~ITABLE(T)() \
{ \
for (unsigned i = 0; i < size; i++) \
delete[] v[i].val; \
delete[] v; \
} \
\
void ITABLE(T)::define(int key, T *val) \
{ \
assert(key >= 0); \
unsigned int h = (unsigned int)(key); \
unsigned n; \
for (n = unsigned(h % size); \
v[n].key >= 0; \
n = (n == 0 ? size - 1 : n - 1)) \
if (v[n].key == key) { \
delete[] v[n].val; \
v[n].val = val; \
return; \
} \
if (val == 0) \
return; \
if (used*FULL_DEN >= size*FULL_NUM) { \
IASSOC(T) *oldv = v; \
unsigned old_size = size; \
size = next_ptable_size(size); \
v = new IASSOC(T)[size]; \
for (unsigned i = 0; i < old_size; i++) \
if (oldv[i].key >= 0) { \
if (oldv[i].val != 0) { \
unsigned j; \
for (j = (unsigned int)(oldv[i].key) % size; \
v[j].key >= 0; \
j = (j == 0 ? size - 1 : j - 1)) \
; \
v[j].key = oldv[i].key; \
v[j].val = oldv[i].val; \
} \
} \
for (n = unsigned(h % size); \
v[n].key >= 0; \
n = (n == 0 ? size - 1 : n - 1)) \
; \
delete[] oldv; \
} \
v[n].key = key; \
v[n].val = val; \
used++; \
} \
\
T *ITABLE(T)::lookup(int key) \
{ \
assert(key >= 0); \
for (unsigned n = (unsigned int)key % size; \
v[n].key >= 0; \
n = (n == 0 ? size - 1 : n - 1)) \
if (v[n].key == key) \
return v[n].val; \
return 0; \
} \
\
ITABLE_ITERATOR(T)::ITABLE_ITERATOR(T)(ITABLE(T) *t) \
: p(t), i(0) \
{ \
} \
\
int ITABLE_ITERATOR(T)::next(int *keyp, T **valp) \
{ \
unsigned size = p->size; \
IASSOC(T) *v = p->v; \
for (; i < size; i++) \
if (v[i].key >= 0) { \
*keyp = v[i].key; \
*valp = v[i].val; \
i++; \
return 1; \
} \
return 0; \
}
// Local Variables:
// fill-column: 72
// mode: C++
// End:
// vim: set cindent noexpandtab shiftwidth=2 textwidth=72:
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